In the construction industry, when concrete is used as a structure, or as a part of a structure, it is often necessary that means be provided for the secure fastening of objects, such as cabling racks and utility walls, to the concrete. This is commonly achieved by casting threaded anchors into the concrete at desired locations. The objects are then fastened to the anchor by means of a bolt.
Anchors in use today are usually molded from plastic or cast from zinc. The anchors, both plastic and zinc, are generally comprised of a tapered cylindircal member, having flanges extending longitudinally along the exterior surface of the cylinder. The purpose of the tapered configuration is to inhibit the anchor from being pulled out of the concrete when a tensile force is applied. The flanges prevent the anchor from turning in the concrete when a torque is applied.
The existing anchors, however, have several shortcomings. One shortcoming is that their configuration provides a relatively small pullout area of taper, and as a result there is only a limited amount of tensile force resistance.
Another shortcoming relates to the inherent weakness of the material used to manufacture the anchors (e.g. zinc or plastic). Because the bolts, which are used to fasten objects to the anchor, are usually made of galvanized steel, the bolt is harder and coarser than the anchor. Consequently, when the bolt is screwed into the anchor the threads of the anchor are often stripped or destroyed so that the fastening is not structurally sound.
In view of the above it is an object of the subject invention to provide a new and improved configuration of threaded anchor which provides greater tensile and torque resistance than obtained by the prior art devices.
It is another object of the subject invention to provide a method of constructing a threading anchor which is very economical, and also provides a structurally sound fastening means.